The present invention relates to a metal gasket with a support bead for providing a balanced surface pressure around a fluid hole of an internal combustion engine.
In the internal combustion engine, bolts are arranged around the cylinder bores to securely seal therearound. Other holes, such as water holes, oil holes and so on, are simply situated near the cylinder bores, and are sealed by the surface pressures formed by the bolts arranged around the cylinder bores.
In a cylinder head gasket, therefore, when the bolts are tightened, the surface pressures formed around the cylinder bores are generally equal, and the portions around the cylinder bores are securely sealed by the surface pressures formed by the tightened bolts. However, the areas around other holes, such as water hole, oil holes and so on, are not equally compressed.
For example, in case a water hole with a sealing bead is situated near a bolt hole, where a surface pressure is mainly formed by one bolt passing through the bolt hole, when the bolt is tightened, the sealing bead around the water hole does not receive an equal tightening pressure. Generally, a bolt side of the bead is tightened strongly, while the portion of the bead away from the bolt is not tightened strongly.
In order to securely seal around the fluid hole, such as the water hole and oil hole, it is preferable to form a surface pressure on the sealing means as equal as possible. Also, it is preferable to support the engine part at an edge portion of the gasket so that the gasket does not vibrate at the edge portion.
In U.S. Pat. No. 5,078,413, two beads are formed around a cylinder bore to securely seal around the cylinder bore. However, the beads do not form an equal surface pressure around the cylinder bore.
In U.S. Pat. No. 4,834,399, a bead is formed around the edge of the gasket. The bead supports the edges of the gasket properly, but a local surface pressure is not supported.
In view of the foregoing, the present invention has been made, and an object of the present invention is to provide a metal gasket, which can provide a surface pressure for sealing means around a fluid hole as equal as possible.
Another object of the invention is to provide a metal gasket as stated above, which can seal securely around the fluid hole.
A further object of the invention is to provide a metal gasket as stated above, wherein the equal surface pressure is formed regardless the rigidity of an engine part.
A still further object of the invention is to provide a metal gasket as stated above, which can support a local pressure applied thereto.
Other objects and advantages of the invention will be apparent from the following description of the invention.